In the wireless world, a subscriber to a mobile service is typically identified through the number allocated to its mobile station Mobile Directory Number (MDN), an example of which is the Mobile Station Integrated Services Digital Network (MSISDN) number used within Global System for Mobile Communications (GSM). Each MDN is typically assigned to a unique mobile service provider. In most countries, different mobile service providers are provided with distinct, non-overlapping ranges of MDNs, and changing one's service provider thus requires changing one's MDN. The introduction of Mobile Number Portability (MNP) solves this problem by enabling users to keep their MDN while changing service providers. From a consumer perspective, MNP removes a barrier to change. Indeed, the transition between mobile service providers is easier for users who can now change service providers without dealing with issues that were typically associated with such a transition, for instance expenses related to modifying materials of business (invoices, business cards, etc.). MNP also allows consumers to pursue better service or rates with a new service provider and has the effect of allowing service providers to compete fairly, thus making the market more competitive by alleviating vendor lock-in. However, one drawback of MNP is the need to identify the service provider(s) currently serving the MDN for a call or message to find its way to the intended recipient.
Other issues arise with the proliferation of Instant Messaging (IM) services, which solve the growing desire to communicate faster by allowing for near-real time text-based communication. In IM, users exchange messages through an IM service, to which they are continually connected. “Presence management”, i.e. knowing the availability of a user on one's list of contacts for receiving messages along with what system the user resides on, forms an important part of the IM system. Over the past few years, availability of IM has spread from initially only dial-up Internet users to include users of mobile devices, such as cellular phones and Personal Digital Assistants (PDAs). As mobile service providers are now launching their own mobile IM services, there is an increasing need for these different IM services to work cooperatively in order to ensure successful operation of the overall IM system. Indeed, although mobile IM users are often not aware of the mobile service providers serving other IM users on their list of contacts, they should be able to exchange IM messages with these contacts, regardless of whether they are served by different service providers. Another concern arises from the fact that users of mobile IM services may choose to be identified in a given IM community through an Internet address, which is typically different from their MDN. Indeed, mobile IM users may want to protect the privacy of their MDN or prefer to use a friendlier address than their MDN for the purpose of sending IM messages. As a result, a mobile IM user adding another user as a contact does so using the contact's MDN, as he/she is typically unaware of the corresponding Internet address. In order to route subsequent IM messages to this newly added contact, the mobile user's IM service will therefore need to retrieve the contact's Internet address by querying a remote system using the MDN as an input key. Although this transaction has been standardized by the Open Mobile Alliance (OMA) and by the GSM Association (GSMA), the issue of identifying the remote entity to query still remains to be solved.
Further issues arise when the scope of IM services is expanded to enable users of Internet IM services to interconnect with users of mobile IM services. In this case, users of Internet IM services are allowed to add as contacts and exchange messages with users of mobile IM services, and vice-versa. However, Internet IM Service Providers (IISPs) do not have access to the infrastructures of mobile service providers such as MNP. As a result, when an Internet IM user wants to interact with a mobile IM user, it becomes difficult for the IISP, which serves the Internet IM user, to identify the mobile service provider that should be queried to retrieve the Internet address corresponding to the MDN of the newly added contact (mobile IM user). In addition, some IISPs allow Internet addresses that cannot be mapped to a unique IISP, making the identification task even more complex as users are no longer uniquely identified through their Internet address. Indeed, with the event of Passport Technology, a user belonging to two distinct Internet IM communities can be identified in these two Internet IM communities using the same Internet address. A user of a mobile IM service wanting to exchange messages with a user of an Internet IM service typically does so by adding the Internet address of this new contact in his/her contact list. As a given Internet address can be valid for more than one Internet IM service, as well as point to entirely different users in different Internet IM services, the mobile service provider will therefore have difficulty determining, based solely on the contact's Internet address, which Internet IM service to contact to direct IM messages. Routing traffic between IM systems can thus prove cumbersome, unless there is provided a detailed mapping, which associates each user's Internet address or MDN to the corresponding IM service.
As known in the art, some solutions have been envisaged for mapping MDNs to their serving mobile service providers. One prior art method involves the Signaling System No. 7 (SS7) network, which interconnects the mobile service providers' infrastructures. The SS7 network includes repositories called Home Location Registers (HLRs), which can be queried to identify the service provider serving a specific MDN. Indeed, a HLR is a database that contains mobile subscriber information for a wireless service provider's entire subscriber base. Such information includes the unique International Mobile Subscriber Identity (IMSI), service subscription information, and location information to enable the routing of mobile-terminated calls. For example, when a user dials a mobile subscriber's MDN, the HLR is queried based on the MDN to obtain the requisite routing information. When the HLR receives the routing request, it maps the MDN to the IMSI, from which the mobile service provider serving the MDN can be found and the call routed. However, using the SS7 network is expensive and increases the traffic load carried by the network, thus requiring the purchase of additional equipment. Moreover, the SS7 network is not accessible outside of the community of telecommunications service providers and entities such as IISPs therefore have no access to it.
Another prior art solution involves the MNP database (MNP-DB), which is a central repository that contains a mapping between MDNs and the serving service providers for users that have a new address, i.e. have been “ported out”. The MNP-DB is queried for this information to enable a call made to a ported number to be routed to the appropriate mobile network. MNP-DBs are typically managed in a centralized or distributed manner. In the centralized model, a single reference database containing data for all mobile numbers is used. The database is generally managed by a consortium of network service providers, comprising only mobile network service providers or all network service providers involved in routing calls to mobile subscribers. However, one drawback with this method is that mobile service providers need to provide the company operating the MNP-DB with MNP information in order to proceed with manual replacement of outdated records and this management of the database is complex. In the distributed model, multiple databases contain subsets of the total data, for instance each separate database may comprise the numbers assigned to a specific mobile network service provider. Since the full set of information about all mobile numbers is only available from these separated databases when taken as a whole, access to information may prove difficult in this model. Indeed, it becomes complex to identify which database should be queried to get information on a specific mobile number. Also, the distributed model requires connections to all the databases in order to access records.
What is needed therefore is an easier and more efficient way of identifying the mobile service provider or Internet IM Service Provider serving a given user identifier in order to properly route IM traffic in the event of MNP and/or Passport Technology.
The present description refers to a number of documents, the content of which is herein incorporated by reference in their entirety.